1. Field of the Invention
This invention relates to release films and layers and materials formed and released from said release films and layers. It also relates to methods of manufacture of the aforesaid. The invention also relates to release agents.
2. Description of Related Technology
Release films and layers are known, for example U.S. Pat. No. 5,795,649 describes the use of inter alia polyacrylic type release layers on polyester film.
Typically a layer of material is deposited on to a release film which comprises a substrate and a release layer said release layer comprising a release agent. The layer of material is then subsequently released from the release layer/release agent by use of an organic solvent such as acetone. The layer of material released from the release agent/layer may be of a desired quality. For example it is known that metal flakes of a particular quality can be obtained by such a technique which makes them particularly useful inter alia for use as a pigment in coatings such as paints. The plate-like structure obtainable by such a process means that it may be possible, for example, to obtain paint of a more reflective nature which in certain circumstances may be desirable. U.S. Pat. No. 5,135,812 describes optically variable thin film flake and its use in ink and paint vehicles to provide optically variable inks, paints and the like.
There is a need for alternative release films and release agents and release layers comprising said agents. Some of the disadvantages associated with known release films is that it is necessary to use an expensive and environmentally unfriendly solvent to release the deposited material e.g. a metal containing compound—for example U.S. Pat. No. 5,795,649 is limited to the use of organic solvents such as acetone. It is also the case that alternative release films/agents/layers may afford a wider range of material that can be successfully deposited and subsequently released with the possibility that said released material may be of a particularly useful quality, for example it may possess particular optical properties.
EP 0087889 describes the production of vermiculite products and a suspension for use therein.
U.S. 5,571,614 describes polymeric packaging film coated with compositions comprising a layer mineral such as vermiculite and a cross-linked resin. The function of the resin is essentially to bind the vermiculite layer to the substrate, and vermiculite is acknowledged as being particularly suitable for providing gas barrier properties in particular with respect to oxygen. To provide that function the coating layer must remain in position and, to that end, a protective overcoat layer of a film-forming polymeric resin may be applied.
It has unexpectedly been found by the current inventors that films based on the films described in U.S. Pat. No. 5,571,614 are suitable for use as release films and that said release films may be used for making thin layers of material suitable for a number of applications.